Tuesday, 12 January 2016

Mercury Meltdown! Logic in retrograde...

So Mercury is in retrograde right now...wait...you didn't know? Are you telling me you haven't noticed how SHIT you're life has been over the past month? You missed a bus today. Your boss was slightly grumpy last week. And you didn't win the Lotto.See the pattern? That's because relative to Earth right now Mercury is moving backwards in the sky. That must significant somehow, Right?

These guys are certainly worried about it.

They aren't alone the internet is full of dire warnings of the effect of Mercury retrograde. Sleep deprivation, technology malfunction, don't start a relationship, don't have repairs done... the warnings come thick and fast... mostly thick.

So what's the truth? All planets appear in retrograde at some point, Mercury just does it more often.This reversal in direction is simply a factor of two planets relative motion around the Sun. It's an effect of perspective, that's all. You can read more about the actual science of the retrograde here. Ancient astronomers struggled with this, it took the realisation of Copernicus and Galileo that the Earth orbits the Sun and not vice versa to dispell this ignorance. Unfortunately, no one filled in the astrologers and psychics, they still find this retrograde motion mysterious, challenging even.

"Keep in mind that astrology is based on a simple understanding that all the planets in the sky exert their own unique influence on each of us, and the world we live in.... Under this planetary influence (which occurs three times this year), communications of all types go "haywire!" You'll experience misunderstandings and communication failures in such great abundance that you'll look up at the sky and stars and say, "What the hell is going on?" The answer is: Mercury is in Retrograde."

Gravity is simply too weak a force to do so, to exemplify this consider that the gravitational force exerted on you by your nearby coffee table is far greater than that of Mercury. Not only is gravity an extremely weak force, consider that when you lift a fallen orange from the ground you are overcoming the gravitational force exerted by an entire planet, but it's an inverse square law. This means it weakens by the square of the increase in separation.

Let's look at the mutual gravitational force between you and Mercury compared to the gravitational force between yourself and a passing family car, say a Ford Focus.

Using Newton's law of gravitational force, we can compare the mutual gravity between Mercury and you.

Where Fg is the force in Newtons, G is Newton's gravitational constant, M is Mercury's mass and m is your mass, with r representing the average distance between yourself and Mercury.

Hmm... pretty small, it's hard to see how fluctuations in that force could, for example, alter your emotions. Let's see how the force caused by the passing Ford Focus compares, let's say the car is around 2 m from you.

As you can see, the car exerts a gravitational force almost a full order of magnitude greater than Mercury. Can you imagine a system of belief that insists that because a Ford Focus did a u-turn in front of your house, you were in for a shitty week, or should expect major arguments with your partner, or you'll contract fuckin' norovirus? It would be nonsense. And that's an actual change in motion, not an illusion created by relative motion!

So how can so many people experience turmoil during Mercury retrograde, if there's nothing to it? What we have here is ad-hoc reasoning, a person is told Mercury is in retrograde, is also told this can have a negative effect and then goes back selecting all the bad things that happened to them over the past week, forgetting the positive things that also happened, and neglecting to consider the times similar things have happened to them and others when Mercury WASN'T in retrograde. This form of confirmation bias is also responsible for the belief that a full moon can also affect behaviour,

Eccentric Fails To Consider Eccentricity

I came across more Mercury madness when I was recently informed via my twitter feed that there was an important article had I JUST had to read. As this recommendation came from Graham Hancock, a British writer whose work is probably best described as pseudo-archelogy, I suspected that what he calls "important" I may define as "mad as a wasp in an envelope." I was not disappointed.

"This is the story of a quite extraordinary synthesis in the history of archaoastronomy, as the bare bones of an advanced astronomical system are revealed for the first time in a thousand years. It is also the story of two numbers that underpin life on Earth and shape our local reality. And finally it is the story of three non-academic scientists and their quest to tackle some of the most enigmatic questions of our times."

"For the last 20 years, in my spare time, I have been studying the geometry and harmony of the solar system, with particular focus on the way that the inner planets, Venus and Mercury, relate to the Earth. In 1993 I published an observation concerning the orbits and sizes of Earth and Mercury, which had struck me as somewhat eerie. Here is a picture. What I had discovered was that a pentagram produces Mercury’s mean orbit from Earth’s, and that the same proportion relates the physical sizes of the two planets, really quite accurately (see my book for exact figures)."

Lovely fudging here: John tells us how brilliant he is, but declines to provide even the slightest in the way of evidence. He says we need to buy his book for the "exact figures" fair enough... how about any figures? Worry not though. We don't need to do the maths to spot the flaw in John's pattern spotting. Much of the theory seems to depend on the fact the Earth's orbit and Mercury's form a perfect pentagram, which is... err... magic... cause...it just is ok.

Let's take a look at this picture John offers us:

Now what I'm about to do seems picky, but John has implied a strong level of accuracy here. Can you spot the immediate problem with John's diagram and any further conclusions upon which it is based?

John presents Earth and mercury's orbits as circular, planetary orbits are elliptical, not circular, the variation from a perfect circle being known as an Eccentricity, measured from 0 (perfect circle) to 1 (flattened). The eccentricity of Earth's orbit is 0.0167 on average at present. No big deal here. It's pretty much circular. The eccentricity of Mercury's orbit is far greater, at 0,229. Quite far from a perfect circle. Another inaccuracy is the placement of the Sun at the Mercury/Earth system's centre. Stars are not at the centre of their planet's orbits, as very simple diagrams of the solar system suggest. They occupy one of the foci on the semimajor axis of a planets orbit, denoted by F' and F in the following diagram taken from Kepler Observatories.

The greater the eccentricity of the planet's orbit, hence the more elliptical it is, the further the Sun is from the centre of that orbit (technically it's the centre of mass of the sun planet system, but the sun's mass is so much greater than that of Earth of Mercury that the mutual centre of mass is close enough to the sun to ignore in principle).

Here are the focal points in Earth's orbit. You can see that the centre of mass of the Sun/Earth system is quite close to the actual centre of the orbit. As the diameter of Earth's orbit is very large (roughly 300,000,000 km), even this small veriation from centre results in a massive distance, approximately 2500000 km in fact.

Now the focal point in Mercury's orbit. As you'll see the Sun here is considerably far from the centre of the orbit.

Let's see how that roughly looks when put together.

Let's see how John's pentagram looks now in a more accurate picture of Earth and Mercury's orbit. As you'll see the alleged patternicity disappears. The central points no longer touch Mercury's orbit and the Sun is far from dead centre.

The two planets orbits are not concentric circles. Now if you're thinking "well it's still close" remember, John described the high accuracy of his calculations. Also, this kind of patternicity depends on blurring the edges. When we eliminate that fudging, the alleged patterns evaporate.

Your humble author...

Robert is a full member of the Association of British Science Writers and the science editor and a contributor to Scisco media, an up and coming, independent news website. There he writes about topics as varied as quantum physics, cosmology, the environment and breakthroughs in medical science. As well as that, Robert engages with can be loosely described as "evidence" of pseudoscience in order to better further the general public's understanding of science at the Null Hypothesis blog.